Biology subjects

Bugter, J. M.

Publications and source records attributed to Bugter, J. M..

5 recordsLinked to original sources

bioRxiv2024

WNT7B drives a program for pancreatic cancer subtype switching and progression

Hyperactivation of WNT signaling is a well-established hallmark of cancer. Various epithelial cancers express high levels of WNT7B and WNT10A that are not commonly expressed during tissue homeostasis, but rather associate with tissue development and regeneration. Although increased WNT7B/10A expression correlates with aggressive disease and lower patient survival rates, the mechanism by which these WNTs influence cancer progression remains unknown. Here, we use patient-derived organoids to show that tumor-intrinsic expression of WNT7B/10A drives survival and growth of advanced pancreatic ductal adenocarcinoma (PDAC). Bulk and single-cell profiling reveal that WNT7B drives proliferation and promotes expression of a poor prognosis basal-like state by preventing expression of a more differentiated, classical PDAC signature. By generating WNT7B reporter organoids, we show that heterogeneously distributed WNT-high PDAC cells are shifted towards a more basal-like phenotype and stably co-exist with WNT-low/negative lineages. Furthermore, hybrid co-cultures of WNT7B-proficient and -knockout PDAC organoids demonstrate that WNT-sending cells drive survival and proliferation of neighboring WNT-negative cells within the cancer epithelium via short range, cell contact-dependent signaling. In summary, our work uncovers a prominent role of WNT7B/10A in driving PDAC subtype heterogeneity and argues that WNT inhibition may be applied to force a class switch to a more differentiated, less aggressive cancer subtype that correlates with improved therapeutical response.

cancer biology↗

bioRxiv2023

E3 ligases RNF43 and ZNRF3 display differential specificity for endocytosis of Frizzled family members

The transmembrane E3 ligases RNF43 and ZNRF3 perform key tumour suppressor roles by inducing endocytosis of members of the Frizzled (FZD) family, the primary receptors for WNT. Loss-of-function mutations in RNF43 and ZNRF3 mediate FZD stabilisation and a WNT-hypersensitive growth state in various cancer types. Strikingly, RNF43 and ZNRF3 mutations are differentially distributed across cancer types, raising questions about their functional redundance. Here, we compare the efficacy of RNF43 and ZNRF3 of targeting different FZDs for endocytosis. We find that RNF43 preferentially downregulates FZD1/FZD5/FZD7, while ZNRF3 displays preference towards FZD6/FZD10. We show that the RNF43 transmembrane domain (TMD) is a key molecular determinant for inducing FZD5 endocytosis. Furthermore, a TMD swap between RNF43 and ZNRF3 re-directs their preference for FZD member downregulation. We conclude that RNF43 and ZNRF3 preferentially downregulate specific FZDs by a TMD-dependent mechanism. In accordance, tissue-specific expression patterns of FZD homologues correlate with the incidence of RNF43 or ZNRF3 cancer mutations in those tissues. Consequently, our data point to druggable vulnerabilities of specific FZD receptors in RNF43- or ZNRF3-mutant human cancers.

cell biology↗

bioRxiv2023

Stabilisation of β-Catenin-WNT signalling by USP10 in APC-truncated colorectal cancer drives cancer stemness and enables super-competitor signalling

The contribution of deubiquitylating enzymes to {beta}-Catenin stabilisation in intestinal stem cells and colorectal cancer (CRC) is poorly understood. Here, we report the deubiquitylase USP10 as an APC-truncation- specific enhancer of {beta}-Catenin stability, potentiating WNT signalling in CRC and cancer stem cells. Mechanistically, interaction studies in various CRC cell lines and in vitro binding studies, together with computational modelling, revealed that USP10 binding to {beta}-Catenin is mediated via the unstructured N-terminus of USP10 and requires the absence of full-length APC. Notably, loss of USP10 in CRISPR engineered intestinal organoids reduces tumorigenic properties of CRC and blocks the super competitor-signalling of APC-mutated CRC. Furthermore, reduction of USP10 induces the expression of differentiation genes, and opposes the APC-truncated phenotype in an intestinal hyperplasia model of D.melanogaster. Taken together, our findings reveal USP10s role in intestinal tumourigenesis by stabilising {beta}-Catenin, leading to aberrant WNT signalling, enhancing cancer cell stemness and implicate the DUB USP10 as a cancer specific therapeutic vulnerability in Apc truncated CRC.

cancer biology↗

bioRxiv2022

RNF43 mutations facilitate mucinous colorectal cancer metastasis via formation of a tumour-intrinsic niche

Colorectal cancer (CRC) progression is characterised by a remarkable increase in plasticity and cellular heterogeneity. The ability of cells to shift states and adopt mixed lineage potential exacerbates during metastasis and associates with poor patient survival. How these atypical differentiated states emerge and drive cancer progression however has remained unclear. Here, we investigate this issue for BRAF-mutant CRC that commonly arise via the serrated pathway and are linked to poor prognosis via incompletely understood progression steps. Using patient-derived organoids, gene editing and murine tumour models, we show that mutations in RNF43, a regulator of WNT receptor abundance, endow BRAF-mutant CRC with metastatic capacity by driving a non-dividing tumour-intrinsic niche cell (TINC) state that provides growth factor self-sufficiency to the cancer tissue. TINCs are enriched in RNF43-mutant, mucinous and metastatic samples of human CRC, and ablation of TINCs lead to re-acquired external growth factor dependency during CRC organoid outgrowth. Together, our findings uncover a mechanism by which tumours leverage cellular plasticity to mediate self-organised stem- and niche-cell interactions. Our results argue that formation of a tumour-intrinsic niche is a prerequisite for BRAF-mutant CRC seeding to distant organs and that interference with niche formation may help avoid metastatic relapse.

cancer biology↗

bioRxiv2019

RNF43 truncating mutations mediate a tumour suppressor-to-oncogene switch to drive niche-independent self-renewal in cancer

Wnt/{beta}-catenin signalling is a primary pathway for stem cell maintenance during tissue renewal and a frequent target for mutations in cancer. Impaired Wnt receptor endocytosis due to loss of the ubiquitin ligase RNF43 gives rise to Wnt-hypersensitive tumours that are susceptible to anti-Wnt-based therapy. Contrary to this paradigm, we identify a class of RNF43 truncating cancer mutations that strongly induce {beta}-catenin-mediated transcription, despite exhibiting retained Wnt receptor downregulating activity. Mechanistically, these RNF43 mutants trap Casein Kinase (CK)1 at the plasma membrane, which prevents {beta}-catenin turnover and propels ligand-independent Wnt target gene transcription. When introduced in human colon stem cells, these oncogenic RNF43 mutants cooperate with p53 loss to drive a niche-independent program for self-renewal and proliferation. Importantly, onco-RNF43 mutations, unlike conventional LOF RNF43 mutations, confer resistance to anti-Wnt-based therapy. Our data demonstrate the relevance of studying patient-derived mutations for understanding disease mechanisms and improved applications of precision medicine.

cancer biology↗